I want to select one column two time from a table.
E.g
( Select rent as rent1, rent as rent2 From Expense)
But I don't know how I can Select this column multiple time as each has its own Where Clause.
Means I want to select One Column two time On two different condition.
Use a union
select test, 'rent1' from tableA where condA
union
select test, 'rent2' from tableA where condB
If you would want to have both values in one result line (can't think of a reason why you would want this, but anyway...) you could use something like a self-join:
select a.rent as rent1, b.rent as rent2
from Expense a,
Expense b
where a.condition
and b.condition
and a/b-join-condition
Related
I want to get AVG values, depending upon the values of two columns.
Here is my table example:
And this is what I need to get:
I'm using that code to get required data but it gives me average for issue not issue and owner.
Here is my code;
select issue, owner, AVG(time) from myTable group by issue, owner
Any suggestion about that?
You can use below query
select issue, owner, avg(time) over() from mytable
I've designed a migration script and as the last sequence, I'm running the following two lines.
select count(*) from Origin
select count(*) from Destination
However, I'd like to present those numbers as cells in the same table. I haven't decided yet if it's most suitable to put them as separate rows in one column or adjacent columns on one row but I do want them in the same table.
How can I select stuff from those selects into vertical/horizontal line-up?
I've tried select on them both with and without parentheses but id didn't work out (probably because of the missing from)...
This questions is related to another one but differs in two aspects. Firstly, it's much more to-the-point and clearer states the issue. Secondly, it asks about both horizontal and vertical line-up of the selected values whereas the linked questions only regards the former.
select
select count(*) from Origin,
select count(*) from Destination
select(
select count(*) from Origin,
select count(*) from Destination)
You need to nest the two select statements under a main (top) SELECT in order to get one row with the counts of both tables:
SELECT
(select count(*) from Origin) AS OriginCount,
(select count(*) from Destination) AS DestinationCount
SQLFiddle for the above query
I hope this is what you are looking for, since the "same table" you are mentioning is slightly confusing. (I'm assuming you're referring to result set)
Alternatively you can use UNION ALL to return two cells with the count of both tables.
SELECT COUNT(*), 'Origin' 'Table' FROM ORIGIN
UNION ALL
SELECT COUNT(*), 'Destination' 'Table' FROM Destination
SQLFiddle with UNION ALL
SQLFiddle with UNION
I recommend adding the second text column so that you know the corresponding table for each number.
As opposed to simple UNION the UNION ALL command will return two rows everytime. The UNION command will generate a single result (single cell) if the count of rows in both tables is the same (the same number).
...or if you want vertical...
select 'OriginalCount' as Type, count(*)
from origin
union
select 'DestinationCount' as Type, count(*)
from destination
I have query like-
select work_Id, startdate,work_per from Work a
where work_per is not null
and StartDate = (select max(StartDate) from Work b where a.work_Id=b.work_Id)
i want to create a package in ssis for this query..
i am face problem in giving condition.in
select max(StartDate) from Work b where a.work_Id=b.work_Id.
here i am checking column a.work_Id's values to b.work_Id.
i really don't know how can i check it in ssis. i tried with condition split but it filter only one table's value only.
and i dont want to use any query in package.. plz give some suggestions..
You can use MERGE JOIN transformation to achieve this. It will have two inputs.
1) select work_Id, startdate,work_per from Work a where work_per is not null
2) select work_Id,max(StartDate) as StartDate from Work b group by b.work_Id
These two inputs will be joined in MERGE JOIN on Work_ID and Start_Date.
Hope this will help..!!
Thanks,
Swapnil
Hello I'm struggling to get the query below right. What I want is to return rows with unique names and surnames. What I get is all rows with duplicates
This is my sql
DECLARE #tmp AS TABLE (Name VARCHAR(100), Surname VARCHAR(100))
INSERT INTO #tmp
SELECT CustomerName,CustomerSurname FROM Customers
WHERE
NOT EXISTS
(SELECT Name,Surname
FROM #tmp
WHERE Name=CustomerName
AND ID Surname=CustomerSurname
GROUP BY Name,Surname )
Please can someone point me in the right direction here.
//Desperate (I tried without GROUP BY as well but get same result)
DISTINCT would do the trick.
SELECT DISTINCT CustomerName, CustomerSurname
FROM Customers
Demo
If you only want the records that really don't have duplicates (as opposed to getting duplicates represented as a single record) you could use GROUP BY and HAVING:
SELECT CustomerName, CustomerSurname
FROM Customers
GROUP BY CustomerName, CustomerSurname
HAVING COUNT(*) = 1
Demo
First, I thought that #David answer is what you want. But rereading your comments, perhaps you want all combinations of Names and Surnames:
SELECT n.CustomerName, s.CustomerSurname
FROM
( SELECT DISTINCT CustomerName
FROM Customers
) AS n
CROSS JOIN
( SELECT DISTINCT CustomerSurname
FROM Customers
) AS s ;
Are you doing that while your #Tmp table is still empty?
If so: your entire "select" is fully evaluated before the "insert" statement, it doesn't do "run the query and add one row, insert the row, run the query and get another row, insert the row, etc."
If you want to insert unique Customers only, use that same "Customer" table in your not exists clause
SELECT c.CustomerName,c.CustomerSurname FROM Customers c
WHERE
NOT EXISTS
(SELECT 1
FROM Customers c1
WHERE c.CustomerName = c1.CustomerName
AND c.CustomerSurname = c1.CustomerSurname
AND c.Id <> c1.Id)
If you want to insert a unique set of customers, use "distinct"
Typically, if you're doing a WHERE NOT EXISTS or WHERE EXISTS, or WHERE NOT IN subquery,
you should use what is called a "correlated subquery", as in ypercube's answer above, where table aliases are used for both inside and outside tables (where inside table is joined to outside table). ypercube gave a good example.
And often, NOT EXISTS is preferred over NOT IN (unless the WHERE NOT IN is selecting from a totally unrelated table that you can't join on.)
Sometimes if you're tempted to do a WHERE EXISTS (SELECT from a small table with no duplicate values in column), you could also do the same thing by joining the main query with that table on the column you want in the EXISTS. Not always the best or safest solution, might make query slower if there are many rows in that table and could cause many duplicate rows if there are dup values for that column in the joined table -- in which case you'd have to add DISTINCT to the main query, which causes it to SORT the data on all columns.
-- Not efficient at all.
And, similarly, the WHERE NOT IN or NOT EXISTS correlated subqueries can be accomplished (and give the exact same execution plan) if you LEFT OUTER JOIN the table you were going to subquery -- and add a WHERE . IS NULL.
You have to be careful using that, but you don't need a DISTINCT. Frankly, I prefer to use the WHERE NOT IN subqueries or NOT EXISTS correlated subqueries, because the syntax makes the intention clear and it's hard to go wrong.
And you do not need a DISTINCT in the SELECT inside such subqueries (correlated or not). It would be a waste of processing (and for WHERE EXISTS or WHERE IN subqueries, the SQL optimizer would ignore it anyway and just use the first value that matched for each row in the outer query). (Hope that makes sense.)
I have a requirement to check if a specific user is already being referenced to one of our transaction tables (we have around 10 transaction tables). I suggested using a VIEW that will contain all the users that are already referenced, then the DEV team could just SELECT through that table to find out if the data they're looking for is there or not,
so here's my query for the view:
SELECT DISTINCT user_ID
FROM transaction_table_1
UNION
SELECT DISTINCT user_ID
FROM transaction_table_2
UNION
SELECT DISTINCT user_ID
FROM transaction_table_3
UNION
SELECT DISTINCT user_ID
FROM transaction_table_4
[...]
Right now it works, but my question is, is this a good idea? The requirement asks that I only provide a script (or a view) and not a stored procedure, I think this would be better with an SP since I could just do a quick IF EXIST() statement for each of the table and just check if the parameter user exists in any of the table, but they really wanted it to be only a script they could check (and no using of variables).
Can you guys give me advice on a better way of doing this requirement, that would have less impact on performance since this may not be the optimized solution for this requirement.
TIA,
Rommel
Well, you can remove the DISTINCT because UNION already makes it :)
SELECT user_ID
FROM transaction_table_1
UNION
SELECT user_ID
FROM transaction_table_2
UNION
SELECT user_ID
FROM transaction_table_3
UNION
SELECT user_ID
FROM transaction_table_4
But since you have to use a view, I don't see how to make it differently.
From a performance point of view I would structure the query slightly differently:
SELECT DISTINCT user_ID
FROM (
SELECT user_ID
FROM transaction_table_1
UNION ALL
SELECT user_ID
FROM transaction_table_2
UNION ALL
SELECT user_ID
FROM transaction_table_3
...
) x
This will reduce the number of unique index scans that need to be done to 1 - rather than having one each time a UNION is performed